In recent years, the number of electric devices and information communication devices having the function of wireless communication has increased, and the demand for chip antennas is also on the rise accordingly, resulting in a need to increase productivity of chip antennas. Under such circumstances, the applicant of the subject application has proposed, as described in Patent Literature 1 provided below, a chip antenna, including an antenna pattern formed through bending a conductive plate, e.g., a metal plate, into a three-dimensional shape, and a base body having a hexahedral shape (rectangular parallelepiped shape), which is formed through injection molding a resin with the antenna pattern as an insert component, and holds the antenna pattern on a surface thereof. Such chip antenna can be manufactured only through the following two steps: subjecting the conductive plate to bending or other such processing to obtain an antenna pattern having a predetermined shape; and forming the base body through injection molding the resin with the antenna pattern as the insert component. As a result, the productivity of the chip antennas can be increased.
In order for the above-mentioned chip antenna including the antenna pattern and the base body holding the antenna pattern to exhibit desired antenna performance with stability, it is necessary to especially hold an antenna part configured to transmit/receive radio waves of the antenna pattern in a state of being held in contact with the base body without a gap therebetween. Accordingly, in the chip antenna of Patent Literature 1, forming, at an edge of the antenna pattern, a tongue-like protruding part to be embedded in the base body, increasing a surface roughness of the antenna pattern at least at a joining surface with the base body, and other such measures are taken.
A chip antenna is generally mounted on a circuit board through so-called reflow processing. The reflow processing is processing in which the chip antenna is placed on solder paste (solder cream) applied on a front surface of the circuit board, and thereafter, all of the chip antenna, the solder paste, and the circuit board are heated at a predetermined temperature (temperature of at least a melting point of the solder or more) for a predetermined period and then cooled in a normal temperature atmosphere, to thereby solder the chip antenna to the circuit board. The reflow processing has an advantage in that chip antennas can be automatically mounted on a plurality of circuit boards at the same time.